WHY OVERHEATING
#1
WHY OVERHEATING
Car didn’t overheat before pulling engine 350sbc Edelbrock 650cfm carb
Upper rad hose
Lower rad hose
Intake near thermostat
rebuild engine with some goodies (cam, intake, aluminum heads ect)
now it overheats at idle.
checked timing and verified gauge readout with temp gun.
thermostat is working as I can see lots of flow through rad cap.
the rad is an older style single core, is it worth upgrading to aluminum with electric fans or just aluminum rad and keep clutch fan?
Upper rad hose
Lower rad hose
Intake near thermostat
rebuild engine with some goodies (cam, intake, aluminum heads ect)
now it overheats at idle.
checked timing and verified gauge readout with temp gun.
thermostat is working as I can see lots of flow through rad cap.
the rad is an older style single core, is it worth upgrading to aluminum with electric fans or just aluminum rad and keep clutch fan?
Last edited by Jonnydepp; 08-15-2020 at 11:23 AM. Reason: Added pics
#2
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Re: WHY OVERHEATING
Doesn't look like overheating to me. Looks just about right. Maybe even a bit on the cool side. ???
What's the problem?
Never hurts to replace the fan clutch, if that's what you've got; or to upgrade to electric, if it can be done in a QUALITY manner.
What's the problem?
Never hurts to replace the fan clutch, if that's what you've got; or to upgrade to electric, if it can be done in a QUALITY manner.
#4
Re: WHY OVERHEATING
Gauge is reading 230-rising, the intake temp (215°) was only after some running time and i killed right after because am worried
What temps should i be worried about under the hood? am i checking right spots?
185° stat but have confirmed it is opening as i can see circulation in the rad with the cap off and stat open
Thanks for the replies guys, going to go for a drive now and bring temp gun with me
What temps should i be worried about under the hood? am i checking right spots?
185° stat but have confirmed it is opening as i can see circulation in the rad with the cap off and stat open
Thanks for the replies guys, going to go for a drive now and bring temp gun with me
#5
Re: WHY OVERHEATING
Do you have a radiator shroud on? Coolant to water ratio? Just trying to establish the basics. Maybe also remove the Tstat and put in a pot of water, bring to boil and verify its opening all the way?
I know they would run these cars pretty hot from the factory... up around 220 IIRC. But running that hot with a 185 Tstat seems like something is off.
I know they would run these cars pretty hot from the factory... up around 220 IIRC. But running that hot with a 185 Tstat seems like something is off.
#6
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#8
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Re: WHY OVERHEATING
I found after my rebuild that the cooling chambers in the block and rebuilt heads released a lot of brown gunk. It took three changes to get most of it out. That stuff clogged up my radiator which apparently was already weak. I flushed the radiator out that helped a lot but car still gets too hot. I just got a better one and am waiting to put it in.
#9
Re: WHY OVERHEATING
The other thing is to make sure you bled the cooling system. Though it sounds like you ran it for a while without the cap, so you may have already done that.
How hot does it get when driving at speed?
How hot does it get when driving at speed?
#10
Re: WHY OVERHEATING
Ok guys, took Tstat out and it opened up nice and full in boiling water.
wanted to see if it would be any different driving without a tstat and it stayed cooler for longer but still eventually got hot.
looking at a set of electric fans/rad from some guy parting out his third gen
how much would this help drop temp?
wanted to see if it would be any different driving without a tstat and it stayed cooler for longer but still eventually got hot.
looking at a set of electric fans/rad from some guy parting out his third gen
how much would this help drop temp?
#11
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Re: WHY OVERHEATING
What's your timing? Retarded timing will cause it to run hot.
What's your idle speed and approximate air fuel ratio?
You sure the fan clutch is good?
220 is basically normal operating temp. How sure are you that this aftermarket gauge is correct? If you are seeing 215 with a laser temp gun - that would be normal.
I highly doubt that dual electric setup would move significantly more air than the shrouded mechanical fan. At any rate if it's overheating with the mechanical then moving more air probably isn't going to entirely fix the situation.
What's the coolant look like? Does it look like chunky diarrhea?
GD
What's your idle speed and approximate air fuel ratio?
You sure the fan clutch is good?
220 is basically normal operating temp. How sure are you that this aftermarket gauge is correct? If you are seeing 215 with a laser temp gun - that would be normal.
I highly doubt that dual electric setup would move significantly more air than the shrouded mechanical fan. At any rate if it's overheating with the mechanical then moving more air probably isn't going to entirely fix the situation.
What's the coolant look like? Does it look like chunky diarrhea?
GD
#12
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Re: WHY OVERHEATING
I think you will like the results after you install those electric fans, my new duals made a world of difference over the stock single electric fan. I just got home from a 90 minutes cruise around town and the temp stayed around 195-200 in stop and go traffic. Check back after you install them.
#13
Re: WHY OVERHEATING
Ok guys, took Tstat out and it opened up nice and full in boiling water.
wanted to see if it would be any different driving without a tstat and it stayed cooler for longer but still eventually got hot.
looking at a set of electric fans/rad from some guy parting out his third gen
how much would this help drop temp?
wanted to see if it would be any different driving without a tstat and it stayed cooler for longer but still eventually got hot.
looking at a set of electric fans/rad from some guy parting out his third gen
how much would this help drop temp?
#15
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Car: 1986 Camaro Drag Car
Engine: 383 on Ethanol
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Re: WHY OVERHEATING
And make sure your lower air dam is attached to the bottom of the radiator support. That makes a HUGE HUGE HUGE difference with these cars.
#16
Re: WHY OVERHEATING
The question of what temperature the engine runs at while driving at speed didn't seem to get answered. This could help determine whether we're dealing with an airflow problem or a cooling system problem.
#17
Supreme Member
Re: WHY OVERHEATING
40* temp drop across radiator at idle looks real decent-seems some sort of coolant flow bollox with the new heads and intake could be causing a hot spot right where the gauge sender is.Fan shroud is not 3rd gen-looks like it may be a B or G body part
#18
Re: WHY OVERHEATING
How far away are the blades from the inner diameter of the shroud? Hard to tell from the photo, but it looks like there's quite a big gap. Too big a gap will result in reduced suction ability for the fan to pull air through the radiator. I don't know what the right number really is, but intuivitely I would think I wouldn't want more than 1/2" from blade tip to shroud. On my Ford Taurus electric fan that I put on my 2nd gen, the blade is about 1/4" away... but I'm running a stock water pump, 180F thermostat, a radiator that most would call a "cheap reman" (aluminum 2 row with plastic tanks) and it has absolutely no problem cooling a ~400 hp small block in 100F weather in traffic with the A/C on... in those conditions it'll get to 190 sometimes, but the high speed will come on and knock that back down in pretty quickly.
Last edited by ULTM8Z; 08-16-2020 at 12:27 PM.
#19
Re: WHY OVERHEATING
Hi everyone,
Installed my new aluminum rad (decided to stick with clutch fan) temps have significantly dropped.
190° cruising and 190-200 stop and go.
I don't believe my car has an air dam but i will be installing one asap.
Also correct about the diameter of the fan a bit far from the shroud (1-1/2" apprx) will be trying to remedy this soon also.
Any recommendations for an air dam? i am thinking a piece of cut aluminum would rivet on there pretty nicely
Installed my new aluminum rad (decided to stick with clutch fan) temps have significantly dropped.
190° cruising and 190-200 stop and go.
I don't believe my car has an air dam but i will be installing one asap.
Also correct about the diameter of the fan a bit far from the shroud (1-1/2" apprx) will be trying to remedy this soon also.
Any recommendations for an air dam? i am thinking a piece of cut aluminum would rivet on there pretty nicely
#20
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Re: WHY OVERHEATING
Not aluminum. Not sheet metal of ANY kind.
First curb you park up to, it'll be mangled.
Instead, get a truck (18-wheeler) mud flap. It'll be somewhat foamy rubber about 3/8" thick. You can find em at any 18-wheeler truck stop along any major freeway. Looks like for you it'll be the 95, 87, or 40. Just hit the road and look for a Blue Beacon, Fruehauf, etc. that caters to commercial traffic. If they don't have it they'll know RIGHT WHERE to send you that does. Cut off a strip a few inches longer than the full length of your radiator lower core support, and wide enough that it comes within an inch or 2 of the ground. Bolt it to the core support with a piece of about 1" aluminum angle and about 6 bolts w/ BIG washers holding the rubber to the angle, and the angle bolted to the car with all of the factory hardware.
It's thick enough to hold its shape under any kind of realistic air pressure, but flexible enough to bend out of the way when you smack a parking lot bumper or driveway ramp, WITHOUT destroying itself. And best of all, YOU can DO THIS, for less than $25 and a half-hour.
First curb you park up to, it'll be mangled.
Instead, get a truck (18-wheeler) mud flap. It'll be somewhat foamy rubber about 3/8" thick. You can find em at any 18-wheeler truck stop along any major freeway. Looks like for you it'll be the 95, 87, or 40. Just hit the road and look for a Blue Beacon, Fruehauf, etc. that caters to commercial traffic. If they don't have it they'll know RIGHT WHERE to send you that does. Cut off a strip a few inches longer than the full length of your radiator lower core support, and wide enough that it comes within an inch or 2 of the ground. Bolt it to the core support with a piece of about 1" aluminum angle and about 6 bolts w/ BIG washers holding the rubber to the angle, and the angle bolted to the car with all of the factory hardware.
It's thick enough to hold its shape under any kind of realistic air pressure, but flexible enough to bend out of the way when you smack a parking lot bumper or driveway ramp, WITHOUT destroying itself. And best of all, YOU can DO THIS, for less than $25 and a half-hour.
#21
Re: WHY OVERHEATING
Hi everyone,
Installed my new aluminum rad (decided to stick with clutch fan) temps have significantly dropped.
190° cruising and 190-200 stop and go.
I don't believe my car has an air dam but i will be installing one asap.
Also correct about the diameter of the fan a bit far from the shroud (1-1/2" apprx) will be trying to remedy this soon also.
Any recommendations for an air dam? i am thinking a piece of cut aluminum would rivet on there pretty nicely
Installed my new aluminum rad (decided to stick with clutch fan) temps have significantly dropped.
190° cruising and 190-200 stop and go.
I don't believe my car has an air dam but i will be installing one asap.
Also correct about the diameter of the fan a bit far from the shroud (1-1/2" apprx) will be trying to remedy this soon also.
Any recommendations for an air dam? i am thinking a piece of cut aluminum would rivet on there pretty nicely
The shroud needs to completely surround the fan and seal to the radiator in order to be effective.
#22
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Car: 1986 Camaro Drag Car
Engine: 383 on Ethanol
Transmission: Automatic
Axle/Gears: 3.90 Currie 9 inch
Re: WHY OVERHEATING
Yep. No bottom half of shroud, and no air dam, either. Double whammy right there. Get them on there and you will be good to go. I bought a new GM air dam from Amazon for $65 + shipping.
You need BOTH of them for that car to run cool
You need BOTH of them for that car to run cool
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